<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>隐式全局变量</title>
</head>
<body>
    <script>
        function f1(){
            num = 200;
            console.log(num);
        }
        f1()
        console.log("外面",num);
    </script>
</body>
</html>